Method of manufacturing light emitting device

ABSTRACT

A method of manufacturing a light emitting device includes mounting an element set on a support substrate. The element set includes an element substrate and a plurality of light emitting elements on the element substrate. Each of the light emitting elements includes a semiconductor layered body having a surface and a pair of electrodes formed on the semiconductor layered body surface. A light reflecting member is provided between the element set and the support substrate. The element substrate is removed from the plurality of light emitting elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of the U.S. patentapplication Ser. No. 15/660,965, filed Jul. 27, 2017 which claimspriority under 35 U.S.C. § 119 to Japanese Patent Application No.2016-148,663, filed on Jul. 28, 2016. The contents of these applicationsare incorporated herein by reference in their entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a method of manufacturing a lightemitting device.

2. Description of Related Art

A light emitting device is known, with a structure of which awhite-color covering member is provided around a semiconductor lightemitting element (for example, see JP 2014-107307 A).

There is a need for further simplification of manufacturing a lightemitting device having such the structure.

SUMMARY

A method of manufacturing a light emitting device includes mounting anelement set on a support substrate. The element set includes an elementsubstrate and a plurality of light emitting elements mounted on theelement substrate. Each of the light emitting elements includes asemiconductor layered body having a surface and a pair of electrodesformed on the semiconductor layered body surface. A light reflectingmember is provided between the element set and the support substrate.The element substrate is removed from the plurality of light emittingelements.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings.

FIG. 1A is a plan view showing a state where an element set of anembodiment according to the present invention is flip-chip mounted.

FIG. 1B is a longitudinal-sectional view showing IB-IB line in FIG. 1A.

FIG. 1C is a cross-sectional view showing IC-IC line in FIG. 1A.

FIG. 2A is a longitudinal-sectional view showing a state where spacebetween an element substrate and a support substrate is filled with alight reflecting member.

FIG. 2B is a cross-sectional view showing a state where space between anelement substrate and a support substrate is filled with a lightreflecting member.

FIG. 3A is a longitudinal-sectional view showing a state where theelement substrate has been removed.

FIG. 3B is a cross-sectional view showing a state where the elementsubstrate has been removed.

FIG. 4A is a longitudinal-sectional view showing a state where aprojection remained on the periphery of the light reflecting member hasbeen removed.

FIG. 4B is a cross-sectional view showing a state where a projectionremained on the periphery of the light reflecting member has beenremoved.

FIG. 5A is a longitudinal-sectional view showing a state where awavelength conversion layer is formed.

FIG. 5B is a cross-sectional view showing a state where a wavelengthconversion layer is formed.

FIG. 6 is a longitudinal-sectional view showing cleaving positions wherelight emitting elements and the support substrates are cleaved.

FIG. 7A is a plan view of the cleaved light emitting device.

FIG. 7B is a cross-sectional view of the cleaved light emitting device.

FIG. 8A is a plan view of the cleaved light emitting device.

FIG. 8B is a cross-sectional view of the cleaved light emitting device.

FIG. 9 is a cross-sectional view showing a light emitting device inwhich two wavelength conversion layers are formed.

DETAILED DESCRIPTION OF EMBODIMENTS

The embodiments will now be described with reference to the accompanyingdrawings, wherein like reference numerals designate corresponding oridentical elements throughout the various drawings.

In the following, a description will be given of an embodiment of thepresent invention with reference to the drawings as appropriate. Notethat, a method of manufacturing a light emitting device described in thefollowing is for embodying the technical idea of the present disclosure.Unless otherwise specified, the present disclosure is not specified tothe following. Further, the description provided in one embodiment orexample is applicable to other embodiment or example. The size orpositional relationship of members in the drawings may be exaggeratedfor the sake of clarity.

A method of manufacturing a light emitting device according to anembodiment includes, in sequence: mounting, on an element mountingsurface of a support substrate, an element set that includes a pluralityof light emitting elements on one element substrate; providing a lightreflecting member between the element set and the support substrate;removing the element substrate from the plurality of light emittingelements; and cleaving the support substrate and the light reflectingmember between the plurality of light emitting elements, so as tosingulate the plurality of light emitting devices.

FIGS. 1A to 1C each show a state where an element set 2, which includesa plurality of light emitting elements 3 on one element substrate 5, ismounted on a support substrate 6. FIG. 1A is a top view. FIG. 1B is asection view taken along line IB-IB in FIG. 1A. FIG. 1C is a sectionview taken along line IC-IC in FIG. 1A.

FIG. 1A shows a state where an element set including five light emittingelements 2 on one element substrate 5 is mounted on a support substrate6. The light emitting elements 3 each have a pair of p-electrode andn-electrode, which are respectively bonded to conductive members 7 ofthe support substrate 6 via bonding members.

Next, as shown in FIGS. 2A to 2B, space is filled with a lightreflecting member 10. FIG. 2A is a longitudinal section view showing astate where space is filled with the light reflecting member 10. FIG. 2Bis a cross section view of such a state. The light reflecting member 10is formed by potting, transfer molding, compression molding or the like.The light reflecting member 10 is formed between the support substrate 6and the element substrate 5, and so as to cover the lateral surface ofeach light emitting element. In more detail, the light reflecting member10 is preferably disposed so as to cover the lateral surface of thesemiconductor layer of each light emitting element 3, and in contactwith the semiconductor layer so as to entirely surround thesemiconductor layer. Thus, in the state where the element substrate 5 isremoved, leakage of light from the lateral surface of the semiconductorlayer is prevented, whereby light can efficiently be emitted from theupper surface of the semiconductor layer.

Further, the light reflecting member 10 preferably fills up the space soas to cover a lower portion of an outer peripheral surface 11 of theelement substrate 5. Thus, the light reflecting member 10 can be formedso that the upper surface of the light reflecting member 10 becomesflush with the upper surface of the semiconductor layer of each lightemitting element 3 when the element substrate 5 is removed.

Further, the light reflecting member 10 is preferably provided so as tofill up the space between each mounted light emitting element 3 and thesupport substrate 6. This structure enhances the strength of the lightemitting device 1. Note that, the light reflecting member 10 disposedbetween each light emitting element 3 and the support substrate 6 may bemade of a material different from a material that covers the lateralsurface of the semiconductor layer of each light emitting element 3.Thus, the light reflecting member disposed at the lateral surface of thesemiconductor layer and the light reflecting member disposed between thelight emitting element 3 and the support substrate 6 can respectively beprovided with proper functions. For example, the light reflecting memberdisposed at the lateral surface of the semiconductor layer may be madeof a material that exhibits high reflectivity, while the lightreflecting member disposed between the light emitting element 3 and thesupport substrate 6 may be made of a material that secures adhesionbetween the light emitting element 3 and the support substrate 6. Inorder to obtain this structure, for example, two types of lightreflecting members differing in the content of a light reflectingmaterial may be employed. Defining the light reflecting member beingsmaller in the content of the light reflecting material as a first lightreflecting member and the light reflecting member being greater in thecontent of the light reflecting material as a second light reflectingmember, by disposing the first light reflecting member between the lightemitting element and the support substrate 6 and thereafter disposingthe second light reflecting member at the lateral surface of each lightemitting element, the light reflecting member structured by two lightreflecting members is obtained.

Next, as shown in FIGS. 3A and 3B, the element substrate 5 for growingthe semiconductor layer having supported the semiconductor layer isremoved. FIG. 3A is a longitudinal section view showing the state afterthe removal of the element substrate 5, and FIG. 3B is a cross sectionview showing such a state. The element substrate 5 can be removed by,for example, laser lift-off which includes operations of: irradiatingthe semiconductor layer from the element substrate 5 side with laserlight that transmits through the element substrate 5 (for example, KrFexcimer laser), so as to cause a decomposition reaction at the interfacebetween the semiconductor layer and the element substrate 5; andremoving the element substrate 5 from the semiconductor layer.

When the element substrate 5 is removed, the light reflecting member 10which had been covering a lower portion of the outer peripheral surface11 of the element substrate 5 may leave a projection 13 along theperiphery of the formed light reflecting member 10. In such a case, theprojection 13 is for example covered with a metal mask provided with anopening, and removed by blast grinding. FIG. 4A is a longitudinalsection view of the state after the removing the projection 13. FIG. 4Bis a cross section view of such a state.

In the state where the element substrate 5 is removed, the upper surface14 of the semiconductor layer of each light emitting element 3 and theupper surface of the light reflecting member 10 are flush with eachother, with no light reflecting member 10 attaching to the upper surface14 of the semiconductor layer. Accordingly, a wavelength conversionlayer 15 can be formed without an operation of removing any lightreflecting member 10 attached to the upper surface 14 of thesemiconductor layer. In order to adjust viscosity or flowability, silica(AEROSIL) or the like may be added to the wavelength conversion layer15. The wavelength conversion layer 15 is desirably formed by spraying,particularly by a pulsed splaying scheme in which a material isintermittently sprayed. By the intermittent spraying, the wavelengthconversion layer 15 can be evenly applied by a smaller injection amount.FIG. 5A is a longitudinal section view showing the state where thewavelength conversion layer 15 is formed. FIG. 5B is a cross sectionview of such a state.

Thereafter, along broken lines 16 shown in FIG. 6, the light emittingelements 3 and the support substrate 6 are collectively cleaved. FIG. 7Ais a plan view of the cleaved light emitting device 1. FIG. 7B is across section view thereof.

One edge 17 in the long-side direction of the light reflecting member 10of the cleaved light emitting device 1 preferably conforms to an edge 18in the long-side direction of the support substrate 6. That is, at leastone of the end surfaces in the long-side direction of the lightreflecting member 10 preferably forms an identical surface with one ofthe end surfaces in the long-side direction of the support substrate 6,and more preferably both the end surfaces of the light reflecting member10 respectively form identical surfaces with both the end surfaces ofthe support substrate 6. This structure allows the light reflectingmember 10 to form the outer surface of the light emitting device 1. Thisincreases the area of the light extraction surface without increasingthe exterior thickness of the light emitting device 1, and thus improvesthe light extraction efficiency. While each edge 19 in the short-sidedirection may be disposed outer than each edge 20 in the short-sidedirection of the support substrate 6, normally, the edge 19 forms anidentical surface with the edge 20 of the support substrate 6, ordisposed inner than the edge 20. As used herein, an identical surface isnot only used just in a strict sense. When the light reflecting member10 is somewhat rounded, the curvature at any point should conform to theend surface of the support substrate 6.

In the state where the support substrate 6 is cleaved, the lightreflecting member 10 as seen from the light extraction surface side isgreater in plane area than the light emitting element 3. In particular,the length in the long-side direction of the outermost shape of thelight reflecting member 10 is preferably about 1.0 to 4.0 times as greatas one side of the light emitting element 3. Specifically, the length ispreferably in a range of about 300 μm to 2000 μm, and more preferablyabout 1000 μm to 1500 μm. The thickness of the light reflecting member10 (the width from the end surface of the light emitting element 3 tothe outermost shape of the light reflecting member 10 as seen from thelight extraction surface side, which is also referred to as the minimumwidth of the light reflecting member 10 at the lateral surface of thelight emitting element 3) is, for example, in a range of about 0 μm to1000 μm, and preferably about 50 μm to 500 μm and about 100 μm to 200μm.

Note that, while the light emitting device 1 shown in FIGS. 7A and 7Bincludes one light emitting element 3, it goes without saying that thenumber of the light emitting element 3 is not particularly specified.The light emitting device 1 may include two or more light emittingelements 3. FIG. 8A is a plan view of a light emitting device 101 thatincludes two light emitting elements 3. FIG. 8B is a cross section viewof the light emitting device 101.

A light emitting device 102 shown in FIG. 9 includes a first wavelengthconversion layer 15 a, and a second wavelength conversion layer 15 bthat covers the first wavelength conversion layer 15 a. By the secondwavelength conversion layer 15 b covering the first wavelengthconversion layer 15 a, a first fluorescent material contained in thefirst wavelength conversion layer 15 a is protected, and thus becomesless prone to deteriorate. As a result, the first fluorescent materialcan fully exhibit its function. Thus, the light emitting device 101being reliable and long in life can be manufactured. Further, the secondwavelength conversion layer shown in FIG. 9 may be a light-transmissiveresin member that contains no fluorescent material. This structureprotects the first fluorescent material contained in the firstwavelength conversion layer.

In the following, a description will be given of each element.

Support Substrate

The support substrate includes an insulating base material, andconductive members that function as a pair of positive and negativeelectrodes.

Base Material

The shape, size, thickness and the like of the base material in onelight emitting device are not particularly specified, and can be set asappropriate. While it depends on the material of the base material, andthe type and structure of the light emitting element mounted thereon,the thickness of the base material is, for example, preferably about 470μm or smaller, more preferably about 370 μm or smaller, about 320 μm orsmaller, about 270 μm or smaller, and more preferably about 200 μm, 150μm, 100 μm or smaller. Further, in view of strength and the like, thethickness is preferably about 20 μm or greater. In order to reliablyobtain the strength of the entire support substrate, the flexuralstrength of the base material is preferably equivalent to the strengthof the support substrate stated above, for example, about 300 MPa orgreater, and more preferably about 400 MPa or greater, and about 600 MPaor greater.

The planar shape of the base material is, for example, a circle, apolygon such as a quadrangle, or any shape similar to the foregoingshapes. Among others, the planar shape of the base material ispreferably a rectangle, that is, a shape being elongated in thelong-side direction. The base material is preferably greater in planearea than the light emitting element, which will be described later. Inthe case where one light emitting element 3 is mounted on one lightemitting device, the length in the long-side direction of the lightemitting device is preferably about 1.5 to 5 times, more preferablyabout 1.5 to 3 times, as great as one side of the light emitting element3. Further, the length in the short-side direction of the light emittingdevice is preferably about 1.0 to 2.0 times, more preferably about 1.1to 1.5 times, as great as one side of the light emitting element. In thecase where a plurality of light emitting elements 3 is mounted on onelight emitting device, the length can be adjusted as appropriate inaccordance with the number. For example, in the case where two or threelight emitting elements 3 are mounted in the long-side direction, thelength in the long-side direction of the light emitting device ispreferably about 2.4 to 6.0 times or about 3.5 to 7.0 times as great asone side of the light emitting element.

As to the strength of the support substrate, in the thickness rangestated above, preferably the flexural strength is 300 MPa or greater,more preferably 400 MPa or greater, and further preferably 600 MPa orgreater. Here, the flexural strength refers to the measurement valueobtained by the 3-point flex test with a commercially available strengthtester, for example a tester available from Instron.

The base material structuring the support substrate may be any material,so long as the linear expansion coefficient thereof falls within a rangeof ±10 ppm/° C. as great as the linear expansion coefficient of thelight emitting element. Preferably, the linear expansion coefficientfalls within a range of ±9 ppm/° C., ±8 ppm/° C., ±7 ppm/° C., or ±5ppm/° C. Note that, in the present embodiment, the linear expansioncoefficient refers to the value measured by the TMA scheme. At least oneof, preferably both of, α1 and α2 should satisfy the value.

The base material may be, for example, metal, ceramic, resin,dielectric, pulp, glass, paper, or a composite material of the foregoingmaterials (e.g., a composite resin), or a composite material of any ofthe foregoing materials and a conductive material (e.g., metal, carbon,or the like). The metal may be copper, iron, nickel, chromium, aluminum,silver, gold, titanium, or alloy containing any of the foregoing metals.The ceramic may be aluminum oxide, aluminum nitride, zirconium oxide,zirconium nitride, titanium oxide, titanium nitride, or a mixture of anyof the foregoing material. The composite resin may be glass epoxy resinor the like.

In particular, the base material suitably contains resin. The resin maybe any resin so long as it is used in the field of the art.Specifically, the resin may be epoxy resin, bismaleimide-triazine (BT)resin, polyimide resin, cyanate resin, polyvinyl acetal resin, phenoxyresin, acrylic resin, alkyd resin, urethane resin or the like.

Whatever the type, the resin preferably exhibits a glass-transitiontemperature of, for example, about 250° C. or greater, and morepreferably, about 270° C. or greater, about 280° C. or greater, about300° C. or greater, about 320° C. or greater. Note that, theglass-transition temperature may be measured by any of, for example, amethod of measuring a change in mechanical property, heat absorption, orheat generation while gradually raising or lowering the temperature of asample (TMA, DSC, DTA or the like), and a method of measuring a responsefrom a dynamic viscoelasticity test sample while changing the frequencyof cyclic force applied to the sample.

Whatever the type, in order for the resin to have a linear expansioncoefficient of ±10 ppm/° C. as great as the linear expansion coefficientof the light emitting element, or to increase the thermal emissivity,the resin preferably contains filler, for example, an inorganic materialas filler. Combining the type, amount and the like of such filler asappropriate, the linear expansion coefficient of the base material canbe adjusted.

The filler and the inorganic material may be, for example, borateparticles coated with hexagonal boron nitride, alumina, silicas (naturalsilica, molten silica and the like), metal hydrate (aluminum hydroxide,boehmite, magnesium hydroxide and the like), molybdenum compounds(molybdenum oxide and the like), zinc borate, zinc stannate, aluminumoxide, clay, kaolin, magnesium oxide, aluminum nitride, silicon nitride,talc, calcined clay, calcined kaolin, calcined talc, mica, glass shortfibers (glass fine powders such as E glass, D glass, glass cloth and thelike), heat-shrinkable filler such as hollow glass fibers, zirconiumphosphate and the like, styrene-based rubber powder, butadiene-basedrubber powder, acryl-based rubber powder, silicone rubber powder and thelike, and core-shell type rubber powder (styrene-based rubber powder,butadiene-based rubber powder, acryl-based rubber powder, siliconerubber powder and the like) or the like. In particular, allowing resinto contain, by a great amount, filler or an inorganic material thatexhibits high thermal conductivity, the thermal emissivity can beadjusted. For example, with glass cloth, an inorganic material can becontained in the glass cloth by 50 wt % or greater, by 70 wt % orgreater, and by 90 wt % or greater.

Further, the resin may contain pigment. The pigment may be carbon black,titanium oxide or the like.

Conductive Members

A pair of conductive members should be formed at least at the uppersurface of the support substrate (on the side where the light emittingelement is mounted). In this case, at least part of the edge of eachconductive member is preferably formed so as to conform to part of theedge of the upper surface of the support substrate. In other words,preferably part of the end surface of each conductive member and themounting surface of the support substrate are formed to become anidentical surface. Thus, in mounting the light emitting device on amounting substrate, the mounting substrate and the end surface of theconductive member can be brought into contact with each other (orbrought in extreme proximity to each other). Thus, the mountability ofthe light emitting device improves. As used herein, the identicalsurface means that any height difference does not exist or littleexists, and irregular shapes of about several micrometers to ten-oddmicrometers are tolerated. In the present specification, the termidentical surface is used in this sense in the following.

Each conductive member has an element connected portion that isconnected to an electrode of the light emitting element at the uppersurface of the support substrate, and an externally connected portionthat is connected to an external element outside the light emittingdevice. In addition to the upper surface of the support substrate,preferably the externally connected portion is also provided at thelower surface of the support substrate. For example, preferably theconductive member is: (i) provided so as to extend from the uppersurface to the lateral surface; (ii) provided so as to extend from theupper surface to the lower surface through a via or a through holeprovided to penetrate through the base material; or (iii) provided so asto extend from the upper surface to the lower surface via the lateralsurface (for example, to be U-shaped as seen in a section view).

The support substrate may include, in addition to the conductive membersthat function as electrodes, a conductive member that is notelectrically connected to the light emitting element and functions as,for example, a heat dissipation member, a reinforce member and the like.

Further, in the case where a plurality of light emitting elements isdisposed in one light emitting device, one or more additional conductivemembers that electrically connect the plurality of light emittingelements 3 may be included.

Each conductive member may be formed by, for example, a single-layerfilm or a multilayer film of metal such as Au, Pt, Pd, Rh, Ni, W, Mo,Cr, Ti, Fe, Cu, Al, Ag or the like, or alloy of the foregoing metals.Among others, metal or alloy that exhibits excellent conductivity andmountability is preferable. Metal or alloy that exhibits excellentbondability and wettability with solder on the mounted side is morepreferable. In particular, in view of heat dissipation property, copperor copper alloy is preferable. At the surface of each conductive member,highly light-reflecting coating of silver, platinum, tin, gold, rhodium,or alloy of foregoing metals may be formed. Each conductive member mayspecifically have a layered structure such as: W/Ni/Au, W/Ni/Pd/Au;W/NiCo/Pd/Au; Cu/Ni/Cu/Ni/Pd/Au; Cu/Ni/Pd/Au, Cu/Ni/Au, Cu/Ni/Ag;Cu/Ni/Au/Ag and the like. Further, each conductive member may bepartially varied in thickness or in the number of layers.

Element Set

In view of productivity, as the element substrate, it is preferable toemploy a substrate for growing a semiconductor layered body of the lightemitting element, which will be described later. Such a substrate may bean insulating substrate such as sapphire (Al₂O₃) or spinel (MgAl₂O₄), ora nitride-based semiconductor substrate. The thickness of the elementsubstrate is, for example, preferably about 190 μm or smaller, and morepreferably about 180 μm or smaller, about 150 μm or smaller.

The element substrate may have a plurality of projections or irregularshapes on its surface. In accordance therewith, for example, on theelement substrate-side surface of the nitride semiconductor layered bodyformed on the plurality of projections or irregular shapes (the surfaceopposite to the surface where the electrodes of the nitridesemiconductor layered body is formed), a plurality of projections orirregular shapes corresponding to the shape of the element substrate maybe formed. Thus, the irregular shapes may have a height in a range ofabout 0.5 μm to 2.0 μm, and a pitch in a range of about 10 μm to 25 μm.The element substrate may have a miscut angle in a range of about 0° to10° relative to a predetermined crystal face such as the C-plane or theA-plane. Note that, the element substrate may have, between the elementsubstrate and the first semiconductor layer, a semiconductor layer, aninsulating layer or the like, as an intermediate layer, a buffer layer,a base layer and the like.

After the element set and the support substrate are bonded to each otherand the light reflecting member is provided between them, the elementsubstrate is removed. The element substrate can be removed by, forexample, laser lift-off which includes operations of: irradiating thesemiconductor layer from the element substrate side with laser lightthat transmits through the element substrate and is absorbed by thesemiconductor layer (for example, when the element substrate is sapphireand the semiconductor layer is GaN-based, KrF excimer laser), so as tocause the semiconductor layer to decompose at the interface between thesemiconductor layer and the element substrate; and removing the elementsubstrate from the semiconductor layer.

The removing the element substrate provides the light emitting devicebeing smaller in size with a reduced thickness. Further, the removingthe element that does not directly contribute to light emission preventslight emitted from the light emitting layer from being absorbed by suchan element. Further, it also reduces light scattering attributed to thelight emitting element substrate. Thus, increased light emissionefficiency and/or increased light emission luminance is/are achieved.

Light Emitting Element

The size, shape, and light emission wavelength of the light emittingelement can be selected as appropriate. When a plurality of lightemitting elements is mounted, they should be arranged regularly orcyclically, such as in a matrix. Further, a plurality of light emittingelements may be connected to each other in series, in parallel, inseries-parallel, or in parallel-series.

The light emitting element includes at least the semiconductor layeredbody. The semiconductor layered body includes, in sequence, an n-typesemiconductor layer, a light emitting layer, and a p-type semiconductorlayer, and contributes to light emission. The thickness of thesemiconductor layered body is preferably about 30 μm or smaller, morepreferably about 15 μm or smaller, about 10 μm or smaller. Further, thesemiconductor layered body is provided with a pair of positive andnegative electrodes at its identical surface.

The type and material of the semiconductor layer are not specificallyspecified. For example, the semiconductor layer may be made of varioustypes of semiconductors such as a group III-V compound semiconductor anda group II-VI compound semiconductor. Specifically, a nitridesemiconductor such as In_(X)Al_(Y)Ga_(1-X-Y)N (0≤X, 0≤Y, X+Y≤1) may beemployed, and InN, AlN, GaN, InGaN, AlGaN, InGaAlN and the like may beused. The thickness and the structure of the layers may be any of thoseknown in the art.

While the shape of the light emitting element or the semiconductorlayered body as seen in a plan view is not particularly specified,preferably it is a quadrangle or a shape similar to a quadrangle. Theupper limit of the size can be adjusted as appropriate depending on thesize of the light emitting device or the characteristics demanded of thelight emitting device. For example, the length of one side of thesemiconductor layered body may be in a range of about several hundredmicrometers to two millimeters. Specifically, the length of one side ofthe semiconductor layered body may be about 1400 μm×200 μm, about 1100μm×200 μm, about 900 μm×200 μm.

Electrodes

A pair of electrodes is formed on an identical surface side of thesemiconductor layered body. This realizes flip-chip mounting in whichthe wiring electrodes of the support substrate and the electrodes of thelight emitting element are bonded to each other as being opposed to eachother.

The electrodes may each be formed by, for example, a single-layer filmor a multilayer film of metal such as Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Tior the like, or alloy of the foregoing metals. Specifically, theelectrodes may each be formed by a multilayer film which includes, insequence from the semiconductor layer side, Ti/Rh/Au, W/Pt/Au, Rh/Pt/Au,W/Pt/Au, Ni/Pt/Au, Ti/Rh or the like.

Light Reflecting Member

The light reflecting member is provided between the element set, whichincludes a plurality of light emitting elements provided on one elementsubstrate, and the support substrate. The light reflecting member isprovided at least around the light emitting elements. The materialthereof is not particularly specified, and may be ceramic, resin,dielectric, pulp, glass, or a composite material of the foregoingmaterials. Among others, resin is preferable for its moldability intoany shape.

The resin may be thermosetting resin, thermoplastic resin or the like.Specifically, epoxy resin, silicone resin, and modified epoxy resin suchas silicone-modified epoxy resin, modified silicone resin such asepoxy-modified silicone resin, hybrid silicone resin, polyimide resin,modified polyimide resin, polyphthalamide (PPA) resin, polyamide (PA)resin, polycarbonate resin, polyphenylenesulfide (PPS) resin, liquidcrystal polymer (LCP) resin, ABS resin, phenolic resin, acrylic resin,PBT resin or the like may be employed.

The light reflecting member is preferably a light shielding materialthat exhibits a reflectivity of 60% or greater, more preferably 70%,80%, or 90% or greater, to light emitted by the light emitting element.Therefore, it is preferable to cause any of the above-stated materials,for example, resin, to contain a light reflecting material, a lightscattering material or a coloring material, or a thermally emissivemember, such as titanium dioxide, silicon dioxide, zirconium dioxide,potassium titanate, alumina, aluminum nitride, boron nitride, mullite,niobium oxide, barium sulfate, various kinds of rare-earth oxides (e.g.,yttrium oxide, gadolinium oxide). The light reflecting member maycontain fibrous filler such as glass fibers or wollastonite, orinorganic filler such as carbon. Further, a material that exhibits highheat dissipation property (e.g., aluminum nitride or the like) may becontained. These additives are preferably contained by, for example, ina range of about 10 wt % to 95 wt %, about 20 wt % to 80 wt %, about 30wt % to 60 wt %, to the total weight of the sealing member.

By causing the light reflecting member to contain a light reflectingmaterial, light emitted by the light emitting element can be efficientlyreflected. In particular, using a material being higher in lightreflectivity than the support substrate (for example, using siliconeresin containing titanium dioxide as the light reflecting member whenaluminum nitride is used as the support substrate), light extractionefficiency of the light emitting device can be enhanced with the supportsubstrate being reduced in size and its handleability being maintained.In the case where just titanium dioxide is contained as the lightreflecting material, titanium dioxide is contained preferably by, in arange of about 20 wt % to 60 wt %, further preferably by about 30 wt %to 50 wt % to the total weight of the light reflecting member.

The light reflecting member is preferably disposed so as to surround thelateral surface of the light emitting element, and in contact with thelight emitting element so as to entirely surround the light emittingelement. Thus, leakage of light from the lateral surface of the lightemitting element is prevented, whereby light can efficiently be emittedfrom the upper surface of the light emitting element. Further, light nothaving its wavelength converted becomes less prone to leak from thelateral surface of the light emitting element, whereby the lightemitting device with reduced color non-uniformity is provided.

Further, the light reflecting member is preferably provided so as tofill up the space between the flip-chip mounted light emitting elementand the support substrate. This enhances the strength of the lightemitting device. Further, the light reflecting member disposed betweenthe light emitting element and the support substrate may be a materialbeing different from the material that covers the lateral surface of thelight emitting element. Thus, the light reflecting member disposed atthe lateral surface of the light emitting element and the lightreflecting member disposed between the light emitting element and thesupport substrate can respectively be provided with proper functions.For example, the light reflecting member disposed at the lateral surfaceof the light emitting element may be made of a material that exhibitshigh reflectivity, while the light reflecting member disposed betweenthe light emitting element and the support substrate may be made of amaterial that secures adhesion between the light emitting element andthe support substrate.

The edge of the sealing member as seen in a plan view (a plan view asseen from the light extraction surface side) may be disposed inner thanor outer than the edge of the support substrate. Further, the edge maybe rounded in the long-side direction or in the direction perpendicularthereto.

Wavelength Conversion Layer

After the light reflecting member is provided between the element setand the support substrate, in the state where the element substrate isremoved from the light emitting element, the wavelength conversion layerthat converts the wavelength of light emitted from the light emittingelement is formed at least at the upper surface of the light emittingelement.

The wavelength conversion layer may be a layer that is formed just by afluorescent material that converts the wavelength of light emitted bythe light emitting element. Alternatively, for example, the wavelengthconversion layer may be made of a light-transmissive material containinga fluorescent material.

Any fluorescent material may be used so long as it is at least excitedby light emitted by the light emitting element and emits light ofdifferent wavelength. For example, the fluorescent material may be (1)an aluminum-garnet-based fluorescent material (e.g., a cerium-activatedyttrium-aluminum-garnet (YAG)-based fluorescent material, acerium-activated lutetium-aluminum-garnet (LAG)-based fluorescentmaterial or the like), (2) a europium and/or chromium-activatednitrogen-containing calcium aluminosilicate (CaO—Al₂O₃—SiO₂)-basedfluorescent material, (3) a europium-activated silicate((Sr,Ba)₂SiO₄)-based fluorescent material, (4) an s-SiAlON-basedfluorescent material, (5) a CASN (CaAlSiN₃:Eu)-based or a SCASN-basednitride-based fluorescent material, (6) a LnSi₃N₁₁-based orLnSiAlON-based rare-earth nitride-based fluorescent material (Ln is arare-earth element), (7) a BaSi₂O₂N₂:Eu-based, Ba₃Si₆O₁₂N₂:Eu-basedoxynitride-based fluorescent material, (8) a Mn⁴⁺-activated fluoridecomplex fluorescent material (e.g., a KSF (K₂SiF₆:Mn)-based fluorescentmaterial), (9) a CaS-based (CaS:Eu), SrGa₂S₄-based (SrGa₂S₄:Eu),SrAl₂O₄-based, ZnS-based sulfide-based fluorescent material, (10) achlorosilicate-based fluorescent material and the like.

Further, the fluorescent material may be a light emitting substance in aform of highly dispersed particles of nano-size, i.e., what is called ananocrystal or quantum dots (Q-Dots), of a semiconductor material suchas a group II-VI, a group III-V, or a group IV-VI semiconductor,specifically, CdSe, core-shell type CdS_(x)Se_(1-x)/ZnS, or GaP. Since aquantum dot fluorescent material is unstable, the surface of theparticles may be coated or stabilized with PMMA (polymethylmethacrylate), silicone resin, epoxy resin, or hybrid resin of theforegoing resins.

Such a structure provides a light emitting device that emits mixed-colorlight (e.g., white-based color) being mixture of primary light of avisible wavelength emitted by the light emitting element and secondarylight being the primary light having undergone wavelength conversion bythe fluorescent material contained in the wavelength conversion layer,and a light emitting device that emits secondary light of a visiblewavelength by being excited by primary light of ultraviolet rays. In thecase where the light emitting device is used for backlight of a liquidcrystal display or the like, it is preferable to employ a fluorescentmaterial that is excited by blue-color light and emits red-color light(e.g., a KSF-based fluorescent material) and a fluorescent material thatis excited by blue-color light and emits green-color light (e.g., aβ-sialon fluorescent material). This increases the color reproductionrange of a display using the light emitting device. When the lightemitting device is used as illumination or the like, a light emittingelement that emits blue-color light, a fluorescent material that emitsyellow-color light, a fluorescent material that emits red-color light,and a light emitting element or a fluorescent material that emitsblue-green-color light may be used in combination.

The shape of the particles of the fluorescent material may be, forexample, crushed, spherical, hollow, porous or the like. Preferably, thefluorescent material has an average particle size (median size) of 50 μmor smaller, 30 μm or smaller, 20 μm or smaller, or 10 μm or smaller. Theaverage particle size can be measured or calculated by processing imagesthat are obtained with commercially available particle counter, particlesize distribution analyzer, or SEM. The above-noted average particlesize refers to the particle size obtained by the air-permeabilityprinciple in F.S.S.S.No (Fisher Sub Sieve Sizer's No).

The light-transmissive material in which the fluorescent material iscontained may be, for example, highly light-transmissive silicone resin,silicone-modified resin, epoxy resin, phenolic resin, polycarbonateresin, acrylic resin, TPX resin, polynorbornene resin, hybrid resin thatcontains at least one of the foregoing resins, glass or the like.

The wavelength conversion layer may be provided as a plurality oflayers. The plurality of layers may contain an identical fluorescentmaterial, or may respectively contain fluorescent materials differing intype, concentration, composition or the like.

In particular, the wavelength conversion layer may at least have a firstwavelength conversion layer that is formed at the upper surface of thelight emitting element, that is, on the light extraction surface of thelight emitting device, and a second wavelength conversion layer thatcovers the first wavelength conversion layer and contains a fluorescentmaterial being of the type differing from that of the first wavelengthconversion layer.

The second fluorescent material contained in the second fluorescentmaterial layer is preferably greater in weather resistance than thefirst fluorescent material contained in the first fluorescent materiallayer. Particularly, the second fluorescent material is preferablyhigher in waterproofness, shorter in light emission wavelength, and lessprone to deteriorate than the first fluorescent material.

Thus, the first fluorescent material being smaller in weather resistanceis protected and becomes less prone to deteriorate. As a result, thefirst fluorescent material is allowed to fully exhibit its function.Thus, a highly reliable and long-life light emitting device ismanufactured.

In the present specification, the light emission wavelength of thefluorescent material refers to the peak wavelength. In general, with anidentical excitation wavelength, the fluorescent material generatesgreater heat in wavelength conversion with a greater light emissionwavelength. Accordingly, when the light emission wavelength of thesecond fluorescent material is shorter than the light emissionwavelength of the first fluorescent material, that is, when the lightemission wavelength of the first fluorescent material is greater thanthe light emission wavelength of the second fluorescent material, heatgenerated at the first fluorescent material tends to become greater.Here, disposing the first fluorescent material layer at a position inclose proximity to other member such as the light emitting device or thesupport substrate, dissipation of the heat from the first fluorescentmaterial is facilitated.

Note that, the term waterproofness refers to resistance to a phenomenonin which the property of the fluorescent material changes due to achange in the original compound state of the base member of thefluorescent material by the base member being dissolved, decomposed,deliquesced, or chemically reacted due to water or moisture. Hence,being high in waterproofness means that the degree of a change inproperty as the fluorescent material is small.

The light-transmissive material can be selected as appropriate from theabove-noted resins that structure the light shielding member. Thematerials that have functions of filling, light diffusion, and coloringcan be selected as appropriate from the above-noted additives havingbeen exemplarily shown as to the base material and the light shieldingmember.

In particular, the light-transmissive material that structures thesecond fluorescent material layer is preferably a material being lowerin gas barrier property and vapor transmissivity than the material ofthe first fluorescent material layer. Thus, the first fluorescentmaterial in the first fluorescent material layer can be effectivelyprotected. Further, the light-transmissive material that structures thefirst fluorescent material layer is preferably better in heatdissipation property and greater in thermal conductivity than the secondfluorescent material layer. This structure improves the reliability ofthe light emitting device. Further, the refractive index of thelight-transmissive material that structures the first fluorescentmaterial layer is preferably equal to or greater than that of thelight-transmissive material that structures the second fluorescentmaterial layer. Thus, light is effectively extracted from thefluorescent material layer, whereby light extraction efficiency of thelight emitting device improves.

The fluorescent material such as the above-noted nanocrystal, quantumdots or the like has, for example, a particle size of 1 nm to 100 nm(including atoms of about 10 to 50 in number). Use of such a fluorescentmaterial reduces the inner scattering. With reduced light innerscattering, components of light that are distributed in the directionperpendicular to the upper surface increase. At the same time, lightdirected to the lateral or lower surface of the light emitting devicereduces. As a result, a further improvement in light extractionefficiency is achieved. For example, when the embodiment of the presentinvention is applied to backlight, efficiency of light entering into thebacklight further increases. Such a fluorescent material referred to asa nanocrystal or quantum dots is generally prone to deteriorate due tomoisture or gas outside the light emitting device, and therefore ispreferably used as the first fluorescent material.

The first fluorescent material may be, representatively, a fluorescentmaterial selected from a group consisting of a KSF-based fluorescentmaterial, a CaS-based fluorescent material, a SrGa₂S₄-based fluorescentmaterial, a SrAl₂O₄-based fluorescent material, a CASN-based fluorescentmaterial, and Q-dots. The second fluorescent material may be afluorescent material selected from a group consisting of analuminum-garnet-based fluorescent material, a β-SiAlON-based fluorescentmaterial, and a chlorosilicate-based fluorescent material.

Further, preferably the average particle size of the first fluorescentmaterial is about 50 μm or smaller, while the average particle size ofthe second fluorescent material is about 30 μm or smaller. The averageparticle size of the first fluorescent material is greater than that ofthe second fluorescent material. In other words, a combination of thefirst and second fluorescent materials in which the second fluorescentmaterial is smaller in average particle size than the first fluorescentmaterial is preferable. Thus, light being the secondary light emitted bythe first fluorescent material is less prone to be blocked by the secondfluorescent material.

The wavelength conversion layer may be formed by, for example, a methodincluding operations of: depositing the fluorescent material by pottingor electrophoretic deposition; and thereafter impregnating thefluorescent material with a light-transmissive material. Alternatively,the wavelength conversion layer may be formed by compression molding,electrostatic coating, printing, bonding a sheet-like first fluorescentmaterial or the like. Here, in the case where the material of the firstwavelength conversion layer is liquid, such as in potting, compressionmolding, printing or the like, a viscosity adjusting agent (e.g., fineparticles of silica) may be added for adjusting viscosity orflowability. Among others, it is preferable to form the wavelengthconversion layer by potting including an operation of supplying slurrycontaining the fluorescent material into the light-transmissive resin.Thus, the wavelength conversion layer can be easily formed at anyposition. Further, the thickness, shape and the like of the wavelengthconversion layer can be easily controlled, whereby the light emittingdevice can be stably manufactured.

Note that, as compared to spraying or the like, potting can relativelyreduce the stress applied to the fluorescent material during manufactureof the light emitting device. Accordingly, in the case where thefluorescent material contained in the wavelength conversion layer is lowin energy absorption (being small in mechanical strength) also, thewavelength conversion layer can be surely formed at a proper portionwithout impairing its shape and characteristics.

In the case where the wavelength conversion layer is formedsimultaneously with a light-transmissive material being a binder bypotting or the like, preferably the wavelength conversion layer isformed so that the concentration of the fluorescent material becomesgreater at the position closer to the light emitting element in thethickness direction of the wavelength conversion layer. To this end, theviscosity of the light-transmissive material is preferably adjustedtaking into consideration of the particle size of the fluorescentmaterial. Thus, the fluorescent material can be directly irradiated withmost of light emitted from the light emitting element, wherebywavelength conversion efficiency improves and color non-uniformity andthe like are prevented. Further, the increased distance between thefluorescent material and the surface of the light emitting devicereduces the influence of the external environment (moisture, gas,ultraviolet rays, oxygen and the like) to the fluorescent material.Further, by placing the fluorescent material in close proximity to othermember of the light emitting device such as the support substrate, thelight shielding member, the light emitting element and the like, heatgenerated by the fluorescent material in wavelength conversion isefficiently dissipated.

Such a wavelength conversion layer can be formed by, for example, amethod including operations of: potting the material of the wavelengthconversion layer; and thereafter stationary placing the potted materialuntil the fluorescent material settles, or applying centrifugal force tothe potted material.

The first wavelength conversion layer is preferably smaller inconcentration of the fluorescent material than the second wavelengthconversion layer. This reduces absorption of primary light or secondarylight by the first fluorescent material that is disposed at the positionnearer to the light emitting element.

The thickness of the first wavelength conversion layer is, for example,preferably 200 μm or smaller, and more preferably 100 μm or smaller. Thefirst wavelength conversion layer is preferably greater in thicknessthan the second wavelength conversion layer.

While the second wavelength conversion layer may be formed by anymethod, preferably the second wavelength conversion layer is formed byspraying on the first wavelength conversion layer. The spraying may beany of the dry scheme or the wet scheme.

Note that, the fluorescent material is not being specified to becontained in the wavelength conversion layer, and may be provided invarious positions in the light emitting device or in members. Forexample, the fluorescent material may be formed as a fluorescentmaterial layer that is applied or bonded to a light-transmissive memberthat contains no fluorescent material.

The wavelength conversion layer may further contain filler (e.g., adiffusing agent, a coloring agent or the like). For example, the fillermay be a crystal or a sintered body of silica, titanium oxide, zirconiumoxide, magnesium oxide, glass, a fluorescent material, or a sinteredbody of a mixture of a fluorescent material and an inorganic binder.Arbitrarily, the refractive index of the filler may be adjusted. Forexample, the refractive index of the filler may be 1.8 or greater.

The shape of the particles of the filler may be crushed, spherical,hollow, porous or the like. The average particle size (median size) ofthe particles is preferably in a range of about 0.08 μm to 10 μm withwhich the light scattering effect is achieved highly effectively. Thefluorescent material and/or the filler may be contained by, for example,in a range of about 10 wt % to 80 wt % to the total weight of thelight-transmissive member.

When spraying is employed as the method of forming the wavelengthconversion layer, particularly the pulsed splaying scheme is preferable,in which spraying is performed in a pulsed manner, that is,intermittently. Spraying intermittently can reduce a fluorescentmaterial injection amount per unit time. Accordingly, by the nozzle thatsprays shifting at a low speed while spraying the material by a smallerinjection amount, the material is applied uniformly to the appliedsurface having irregular shapes. Further, as compared to the continuousspraying scheme, the pulsed splaying scheme can reduce the air velocitywithout reducing the speed of slurry injected from the nozzle. Thus,slurry is supplied to the applied surface in an excellent manner, andthe applied slurry is not disturbed by airflow. As a result, a coatingfilm that exhibits high adhesion between the particles of thefluorescent material and the surface of the light emitting element isformed. Additionally, thin particle layers each containing a particulatefluorescent material can be formed in a plurality of numbers.Controlling the number of layers can improve the thickness precisionthereof. Further, distribution of the fluorescent material becomes lessprone to become uneven. Thus, light having undergone wavelengthconversion uniformly is emitted, whereby color non-uniformity or thelike of the light emitting element is avoided.

The thickness of the wavelength conversion layer is not particularlyspecified. For example, the thickness may be in a range of about 1 μm to300 μm, about 1 μm to 100 μm, about 2 μm to 60 μm, or about 5 μm to 40μm.

Particularly in backlight applications, the wavelength conversion layerhaving such a relatively small thickness further enhances the lightemission efficiency of the light emitting element and the efficiency ofthe backlight. For example, as described above, light emission towardthe light extraction surface increases, and efficiency of light enteringinto the backlight enhances. Further, the amount of thelight-transmissive member in the wavelength conversion layer can bereduced. In the case where resin that exhibits relatively low thermalemissivity is used as the light-transmissive member, reducing theproportion of the resin can reduce heat accumulated by the fluorescentmaterial. At the same time, the contact area between the light emittingelement and the fluorescent material or between the fluorescentmaterials increases, whereby the heat transfer path can be reliablyobtained. Hence, the heat dissipation property of the fluorescentmaterial improves, whereby the light emission efficiency of the lightemitting device improves. Further, since the light extraction surface ofthe light emitting device and a light entering portion of a light guideplate can be mounted in extremely close proximity to each other, lightcan enter the light guide plate of the backlight at higher luminance,improving the efficiency at the backlight.

The wavelength conversion layer may be provided with irregular shapes onits surface. While such irregular shapes may formed by any method, asdescribed above, in the case where a plurality of particle layersincluding a particulate fluorescent material is layered, irregularshapes reflecting corresponding particle size of the fluorescentmaterial are formed on the surface of the wavelength conversion layer.

By such, manufacturing process of the light emitting device can besimplified.

The method of manufacturing a light emitting device of the presentdisclosure is applicable as a method of manufacturing a light emittingdevice as a backlight light source of a liquid crystal display, variousillumination devices, a large display, various display devices such asan advertisement board or a destination board, an image reading devicein a digital video camera, a facsimile, a copier, or a scanner, and aprojector device.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A method of manufacturing a light emittingdevice, the method comprising: mounting an element set on a supportsubstrate, the element set including an element substrate and aplurality of light emitting elements mounted on the element substrate,each of the light emitting elements including a semiconductor layeredbody having a surface and a pair of electrodes formed on thesemiconductor layered body surface; providing a light reflecting memberon the support substrate, the light reflecting member including a firstlight reflecting member and a second light reflecting member, the firstlight reflecting member having a light reflecting material and disposedbetween the light emitting element and the support substrate, the secondlight reflecting member differing from the first light reflecting memberin a content of the light reflecting material and disposed at a lateralsurface of the light emitting element; and removing the elementsubstrate from the plurality of light emitting elements.
 2. The methodaccording to claim 1, wherein the element substrate is a substrate forgrowing the plurality of light emitting elements, and removed with laserlift-off.
 3. The method according to claim 1, wherein the lightreflecting member includes a thermosetting resin containing a lightreflecting member.
 4. The method according to claim 1, wherein, inproviding the light reflecting member between the element set and thesupport substrate, a projection is formed along a periphery of the lightreflecting member.
 5. The method according to claim 1, furthercomprising: providing a wavelength conversion layer that converts awavelength of light emitted by the plurality of light emitting elementson an upper surface of the plurality of light emitting elements afterthe element substrate is removed.
 6. The method according to claim 5,wherein the wavelength conversion layer is provided with spraying. 7.The method according to claim 5, wherein the wavelength conversion layeris provided with potting.
 8. The method according to claim 5, whereinthe wavelength conversion layer includes a first wavelength conversionlayer, and a second wavelength conversion layer that covers the firstwavelength conversion layer.
 9. The method according to claim 1, whereinthe light emitting device includes the plurality of light emittingelements by two or more pieces.
 10. The method according to claim 1,wherein the light reflecting member contains the light reflectingmaterial in a range of 10 wt % to 95 wt %.
 11. The method according toclaim 1, wherein the light reflecting member contains the lightreflecting material in a range of 20 wt % to 80 wt %.
 12. The methodaccording to claim 1, wherein the light reflecting member contains thelight reflecting material in a range of 30 wt % to 60 wt %.
 13. A methodof manufacturing a light emitting device, the method comprising:mounting an element set on a support substrate, the element setincluding an element substrate and a plurality of light emittingelements mounted on the element substrate, each of the light emittingelements including a semiconductor layered body having a surface and apair of electrodes formed on the semiconductor layered body surface;providing a light reflecting member on the support substrate, the lightreflecting member covering a lower portion of an outer peripheralsurface of the element substrate, the light reflecting member includinga first light reflecting member and a second light reflecting member,the first light reflecting member having a light reflecting material anddisposed between the light emitting element and the support substrate,the second light reflecting member having a different light reflectingmaterial from the first light reflecting member thereof and disposed ata lateral surface of the light emitting element; and removing theelement substrate from the plurality of light emitting elements.
 14. Amethod of manufacturing a light emitting device, the method comprising:mounting an element set on a support substrate, the element setincluding an element substrate and a plurality of light emittingelements mounted on the element substrate, each of the light emittingelements including a semiconductor layered body having a surface and apair of electrodes formed on the semiconductor layered body surface;providing a light reflecting member between the element set and thesupport substrate, the light reflecting member covering a lower portionof an outer peripheral surface of the element substrate; and removingthe element substrate from the plurality of light emitting elements. 15.The method according to claim 14, wherein, in removing the elementsubstrate from the plurality of light emitting elements, a projection isformed with the light reflecting member covering the outer peripheralsurface of the element substrate.
 16. The method according to claim 15,further comprising: removing the projection after forming thereof. 17.The method according to claim 14, wherein the light reflecting memberincludes a thermosetting resin containing a light reflecting material.18. The method according to claim 14, further comprising: providing awavelength conversion layer that converts a wavelength of light emittedby the plurality of light emitting elements on an upper surface of theplurality of light emitting elements after the element substrate isremoved, wherein the wavelength conversion layer is provided withspraying.
 19. The method according to claim 14, further comprising:providing a wavelength conversion layer that converts a wavelength oflight emitted by the plurality of light emitting elements on an uppersurface of the plurality of light emitting elements after the elementsubstrate is removed, wherein the wavelength conversion layer isprovided with potting.